Uterine artery blood flow parameters in women with dysfunctional uterine bleeding and uterine fibroids: The effects of tranexamic acid

Abstract

The objective of this study was to investigate the effects of tranexamic acid on uterine vascular resistance in women with dysfunctional uterine bleeding and in women with menorrhagia associated with fibroids. A longitudinal, prospective study was carried out in premenopausal women referred to a gynecological out-patient department with a complaint of menorrhagia. We studied 24 women with dysfunctional uterine bleeding (mean age 38.8 years; normal ultrasound examination, hysteroscopy and endometrial biopsy) and 12 women (mean age 42.8 years) with at least one fibroid greater than 2.0 cm on ultrasound examination. None were on any form of oral contraception or other medication which could influence uterine vascular resistance. All women had normal coagulation and thyroid function tests. Transvaginal scanning was performed using an Aloka SSD 650 machine with a 5-MHz probe and pulsed Doppler. Pulsatility index (PI) and resistance index (RI) were measured from the left and right uterine arteries before and during the second month of treatment with tranexamic acid (1 g orally three times a day). Menstrual blood loss was assessed using a validated pictorial blood chart. In women with dysfunctional uterine bleeding, the mean PI and RI fell significantly with treatment (PI 2.20-1.94, p = 0.0001; RI 0.81-0.77, p = 0.003). There was a reduction of approximately 30% in menstrual blood loss with treatment (210.0-137.6 ml, p = 0.0001). In women with uterine fibroids, there was no significant change in either the PI or the RI with treatment and there was no significant reduction in menstrual blood loss. We conclude that tranexamic acid significantly reduces uterine artery vascular resistance in women with dysfunctional uterine bleeding. This effect is unlikely to be a mechanism for the action of tranexamic acid in reducing menstrual blood loss but may have important implications for women taking this treatment in the long term.